The invention relates to a copying apparatus for copying a magnetic pattern from a master magnetic tape on a duplicate magnetic tape U.S. Pat. No. 3,762,619 discloses a copying apparatus comprising two facing elongate platens having facing substantially parallel sides between which a gap having an entrance end and an exit end is situated, each platen having at least one row of passages in its gap side. Copying means promote the signal transfer from the magnetic pattern on the master magnetic tape and to the duplicate magnetic tape, transport means move the master magnetic tape and the duplicate magnetic tape through the gap in the longitudinal direction of the platens. The master magnetic tape and the duplicate magnetic tape are pressed against one another in the gap, by means of a pressurized fluid fed from the passages in the platens adjacent the two tapes into the gap. In this known apparatus two magnetic tapes are guided between two facing platens in which passages are formed through which pressurized air is fed in to form air cushions which tend to bring the two tapes in contact with one another. In particular at higher speeds of the tapes through the gap air trapped between the tapes after entry into the gap is not expelled effectively in said known apparatus, so that during the movement past the copying means the contact between the tapes is poor. This may result in a poor signal transfer to the duplicate tape and the track pattern on the duplicate tape may deviate from the pattern on the master tape.
In particular in recently proposed magnetic tape systems, such as the R-DAT audio system, it is necessary that during the signal transfer from the magnetic pattern on the master tape to the duplicate tape a comparatively high signal-transfer efficiency for short-wave-length signals is obtained and the track pattern on the master magnetic tape is transferred to the duplicate magnetic tape with an optimum accuracy.
In order to enable an acceptable copying quality to be obtained by means of the prior-art copying apparatus the speed with which the tapes are fed through the gap during duplication can be only slightly higher than the nominal speed. As a result of this, the rate of production of prerecorded duplicate tapes in this apparatus is comparatively low.